pub fn odd_fibnacci_sum(threshold: u32) -> u32 {
    if threshold==1{
        return 0;
    }
    let mut ans=2;
    let mut pre1=1;
    let mut pre2=1;
    while pre2<threshold{
        let sum=pre1+pre2;
        if sum<threshold && sum%2==1{
            ans+=sum;
        }
        pre1=pre2;
        pre2=sum;
    }
    ans
    
}
